Re: [Xen-devel] [PATCH] xen-blkfront: emit KOBJ_OFFLINE uevent when detaching device

From: Vincent Legout
Date: Wed Jul 05 2017 - 08:37:27 EST

On Wed, Jul 05, 2017 at 02:17:24AM -0600, Jan Beulich wrote :
> >>> On 05.07.17 at 10:08, <vincent.legout@xxxxxxxxx> wrote:
> > Without the patch, blkif_release and xlvbd_release_gendisk are never
> > called, and no call to blk_unregister_queue is made.
> But isn't that what needs to be fixed then? The device should be
> removed once its last user goes away (which would be at the time
> the umount is eventually done aiui).

You mean that block-detach should fail if the device is still mounted?
or find a way to wait until all the users are gone?

I don't say that's not what should be done, but that's not what I get.
The device is removed after a block-detach, even if still mounted. So
the system is left in an unstable state without the patch.

I also just saw the --force option of xl block-detach, but from a quick
look it seems this option was actually only in xm and never in xl.